public class ThreadDemo6Random {
    public static void main(String[] args) throws InterruptedException {
        Thread t1=new Thread(()->{
            while (true){
                System.out.println("hello thread1");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        });
        t1.start();
        Thread t2=new Thread(()->{
            while (true){
                System.out.println("hello thread2");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        });
        t2.start();
        Thread t3=new Thread(()->{
            while (true){
                System.out.println("hello thread3");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        });
        t3.start();
        Thread t4=new Thread(()->{
            while (true){
                System.out.println("hello thread4");
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
            }
        });
        t4.start();
        for (int i = 0; i < 3; i++) {
            System.out.println("hello main");
            Thread.sleep(1000);
        }
    }
}
